Most of World's opal gemstones
are found in Australia.
Opal is the
gem of Australia,
which produces 90% of the world's supply, but precious variety Opal
also yields in Ethiopia
Mines are believed to have existed in parts of Africa because
from a cave in Kenya
from around 4,000 years B.C. have recently
come to light.
dubbed Opal the
“Stone of Justice” and Queen Victoria
collected them profusely.
Opal is unique
because its colours and infinite
patterns are not caused through the crystal shape or mineral content as
do all other gems.
Instead Opal is
composed of layers of very small spheres of silica
which have grown around a central nucleus, so it is classified as a
not a mineral
because it does not form a crystal structure.
do not exist
although some people call a semi-clear Opal
Opals are determined
by the space between the spheres, the
patterns in Opals through light interplaying between the spheres.
No two Opals are the same, not even if they are cut from the same
specimen or split.
is the most
precious of patterns.
It displays a mosaic, broad pattern of close-set colours.
are regarded as the
most expensive, with the most valuable
displaying a harlequin.